The Peripheral Component Interconnect (PCI), a local bus standard developed by Intel Corporation, has become the industry standard for providing all primary I/O functions for nearly all classes of computers and other peripheral devices. Some of the computers that employ the PCI architecture, for instance, range from a personal microcomputer (or desktop computer) at a lower entry-level to a server at an upper enterprise-level.
However, while virtually all aspects of the computer technology, such as a processor or memory, advanced dramatically, especially over the past decade, the PCI system architecture has not changed at the same pace. The current PCI system has become considerably outdated when compared to other components of today's technology. This is especially true at the upper enterprise-level. For instance, the current PCI bus system employs a shared-bus concept, which means that all devices connected to the PCI bus system must share a specific amount of bandwidth. As more devices are added to the PCI bus system, the overall bandwidth afforded to each device decreases. Also, as the speed (i.e., MHz) of the PCI bus system is increased, the lesser number of devices can be added to the PCI bus system. In other words, a device connected to a PCI bus system indirectly affects the performance of other devices connected to that PCI bus system.
It should be apparent that the inherent limitation of the PCI system discussed above may not be feasible for meeting the demands of today's enterprises. Many of today's enterprises run distributed applications systems where it would be more appropriate to use an interconnection system that is independently scalable without impacting the existing performance of the current system. E-commerce applications that run in server cluster environments, for example, would benefit tremendously from an interconnection system that is independently scalable from the servers, networks, and other peripherals.
While the current PCI system generally serves the computing needs for many individuals using microcomputers, it does not adequately accommodate the computing needs of today's enterprises. Poor bandwidth, reliability, and scalability, for instance, are just a few exemplary areas where the current PCI system needs to be addressed. There are other areas of concern for the current PCI system. For instance, I/Os on the bus are interrupt driven. This means that the processor is involved in all data transfers. Constant CPU interruptions decrease overall CPU performance, thereby decreasing much of the benefits of increased processor and memory speeds provided by today's technology. For many enterprises that use a traditional network system, these issues become even more significant as the size of the computer network grows in order to meet the growing demands of many user's computing needs.
To combat this situation, a new generation of I/O infrastructure called InfiniBand™ has been introduced. InfiniBand™ addresses the need to provide high-speed connectivity out of the server. It enhances the ability to transfer data better than today's shared bus architectures. InfiniBand™ architecture is a creation of the InfiniBand Trade Association (IBTA). The IBTA has released the specification, “InfiniBand™ Architecture Specification”, Volume 2, Release 1.0.a (Jun. 19, 2001), which is incorporated by reference herein.
Even with the advent of new technologies, such as InfiniBand™, however, there are several areas of computing needs that still need to be addressed. One obvious area of computing needs involves an implementation of any new technology over an existing (or incumbent) system. For instance, installing a new infrastructure would necessitate acquiring new equipment to replace the existing equipment. Replacing the existing equipment is not only costly, but also disruptive to current operation of the enterprise.
This issue can be readily observed if one looks to a traditional network system that includes multiple servers where each server has its own dedicated input/output (I/O) subsystem. A typical dedicated I/O subsystem is generally based on the PCI local bus system and must be tightly bound to the processing complex (i.e., central processing unit) of the server. As the popularity of expansive networks (such as Local Area Network (LAN), Wide Area Network (WAN), InterProcess (IPC) Network, and even the Internet) grows, a typical server of a traditional network system needs to have the capacity to accommodate these network implementations without disrupting the current operation. That is, a typical server in today's network environment must have an I/O subsystem that has the capacity to interconnect the server to these expansive network implementations. Note that while there are certain adapters (and/or controllers) that can be used to accommodate some of these new technologies over an existing network system, this arrangement may not be cost efficient.
FIG. 1A illustrates a prior art network configuration of a server having its own dedicated I/O subsystem. To support network interconnections to various networks such as Fibre Channel Storage Area Network (FC SAN) 120, Ethernet 110, or IPC Network 130, the server shown in FIG. 1A uses several adapters and controllers. The PCI local bus 20 of the server 5 connects various network connecting links including Network Interface Cards (or Network Interface Controllers) (NIC) 40 Host Bust Adapters (HBA) 50, and InterProcess Communications (IPC) adapters 30.
It should be apparent that, based on FIG. 1A, a dedicated I/O subsystem of today's traditional server systems is very complex and inefficient. An additional dedicated I/O subsystem using the PCI local bus architecture is required every time a server is added to the existing network configuration. This limited scalability feature of the dedicated I/O subsystem architecture makes it very expensive and complex to expand as required by the growing demands of today's enterprises. Also, adding new technologies over an existing network system via adapters and controllers can be very inefficient due to added density in a server, and cost of implementation.
Accordingly, it is believed that there is a need for providing a shareable, centralized I/O subsystem that accommodates multiple servers in a system. It is believed that there is a further need for providing an independently scalable interconnect system that supports multiple servers and other network implementations. It is believed that there is yet a further need for a system and method for increasing bandwidth and other performance for each server connected to a network system. It is also believed that there is a need for a system and method that provides a shareable, centralized I/O subsystem to an existing network configuration without disrupting the operation of the current infrastructure, and in a manner that complements the incumbent technologies.